Machine for honing blind-end bores

ABSTRACT

Automatic honing machine for blind-end bores having only a small annular relief groove at the bottom of the bore and comprising a frame, a motor mounted on said frame, an extensible hone actuated by said motor, an axially displaceable conical tie rod disposed along the axis of the hone and coupled to said hone so as to produce the extension thereof, wherein the motor is an electric motor having a stator pivotally mounted on the drive shaft which is supported by a stationary frame and maintained elastically in a position of equilibrium, and means for driving the conical tie rod in axial translation motion which are operated under the control of said pivotal stator in order to produce action on the extension of said hone and in order to control said extension in dependence on the resisting torque produced by the operation of said hone.

United States Patent Garnier Feb. 29, 1972 Estabrook ..51/34 D X Primary Examiner-Othell M. Simpson Attorney-Clelle W. Upchurch s7] 1 ABSTRACT Automatic honing machine for blind-end bores having only a small annular relief groove at the bottom of the bore and comprising a frame, a motor mounted on said frame, an extensible hone actuated by said motor, an axially displaceable conical tie rod disposed along the axis of the hone and coupled to said hone so as to produce the extension thereof, wherein the motor is an electric motor having a stator pivotally mounted on the drive shaft which is supported by a stationary frame and maintained elastically in a position of equilibrium, and means for driving the conical tie rod in axial translation motion which are operated under the control of said pivotal stator in order to produce action on the extension of said hone and in order to control said extension in dependence on the resisting torque produced by the operation of said hone.

6 Claims, 4 Drawing Figures m ted Feb. 29, 1972 2 Sheets-Sheet 1 Patented Feb. 29, 1972 3,645,047

2 Sheets-Sheet z MACHINE FOR HONING BLIND-END BORES This invention is directed to a machine for the automatic honing of blindend bores which are provided only with an annular relief groove at the bottom of the bore.

It is only with the greatest difficulty that blind-end bores can be ground by means of the honing machines which are known at the present time by reason of the fact that the guides at each side of the honing stones call for a substantial clearance at the bottom of the bore.

This is the reason for which this type of operation is still performed by hand by means of extensible hones of cast iron. It is therefore apparent that, both from a qualitative and a quantitative standpoint, the results achieved are dependent on the skill of the operator.

The honing machine according to this invention circumvents the disadvantage referred to in the foregoing and is designed to achieve automatic mechanization of manual movements. To this end, the machine comprises a flexibly mounted electric motor in which the load torque applied to the pivotal stator of the motor controls the expansion of the hone, said stator being maintained in the vicinity of the position which corresponds to equilibrium with the driving torque by means of a spring which is adapted to produce a torque of slightly higher value than said driving torque and which is adapted to actuate means for controlling the hone.

More precisely, the novel machine which comprises a motor for actuating an extensible hone by means of a conical tie rod which is disposed in the axis of the hone and capable of axial displacement so as to produce the extension of the hone, is characterized in that the motor is an electric motor whose stator is pivotally mounted on the drive shaft which is supported by a stationary frame and that the reaction torque of said stator which is normally maintained elastically in a position of equilibrium produces action on the means for driving the conical tie rod in axial translational motion or in other words on the extension of the hone, said extension being thus controlled in dependence on the load torque produced by the operation of the hone.

In a preferred embodiment, the novel honing machine in accordance with the invention is further characterized by the following properties and combinations thereof:

The position of equilibrium of the stator of the motor is ensured by means of an equalizing spring which is interposed between a fixed point of the stator and a fixed point of the frame, an adjusting screw being interposed between one of these points and the corresponding extremity of the equalizing spring.

The means for applying axial translational motion to the tie rod whose cortical head is disposed in the axis of the hone and whose cylindrical body is slidably fitted within an axial bore of the drive shaft comprise a hollow nut screwed onto that end of the drive shaft which carries the hone and a key contained in said nut, said key being adapted to'cooperate with the tie rod body through a diametral opening formed in said drive shaft end. The relative rotation of said nut (which normally tends to rotate with the shaft on which it is screwed) or in other words the axial displacement of said nut and of the tie rod body with respect to the hone is controlled by braking means constituted by a hammer which is adapted to produce action periodically on said nut and is actuated by a single-acting jack. supplied through a valve which is mounted on the frame and controlled by the pivotal stator of the motor.

The part to be honed is supported in a travelling carriage which is adapted to perform a reciprocating movement parallel to the axis of the motor.

The part-holder carriage is mounted on the piston rod of a double-acting jack whose supply is controlled by two end-oftravel valves which are operated by the carriage itself, preferably by means of adjustable stops on said carriage.

The valve which controls the supply of the hammer-operating jack is coupled in series with one of the two valves for controlling the reversal of the carriage so as to initiate the falling motion of the hammer at the same time as the return travel of said carriage.

One embodiment of the honing machine in accordance with the invention is shown diagrammatically and solely by .way of example in the accompanying drawings, in which:

FIG. 1 is a view of the machine which is taken in elevation and in partial longitudinal cross section;

FIG. 2 is a view which is taken at right angles to the preceding and from which the part-holder carriage has been omitted;

FIG. 3 is a fragmentary view which is taken at right angles to FIG. 1 and shows the part-holder carriage;

FIG. 4 is a sectional view taken along line lV-lV of FIG. 3.

In the embodiment which is illustrated in the drawings, the machine comprises a frame 1 which is adapted to support a floating electric motor 2, that is to say a motor which carries out an oscillating movement about its axis. The shafi 3 which is rigidly fixed to the rotor 4 extends beyond the pivotal stator 5 at both ends and rests in the frame 1 by means of ball bearings 6 and 7.

The reaction torque of the stator 5 is counterbalanced by an equalizer spring 8 which is coupled respectively to a radial arm 5a of said stator and to an adjusting screw 9 which is engaged in a lateral extension la of the frame 1, said frame being further adapted to carry two adjustable stops 20a and 20b which cooperate with a radial arm 5b of the floating stator 5 so as to limit the amplitude of pivotal motion of said stator.

The honing means which are actuated by the drive shaft 3 comprise a cylindrical hone 10 which is rigidly fixed to the shaft-end 3a and provided with a conical bore in which is slidably fitted a conical tie rod 1 1 for producing the expansion of the hone.

The axial translational motion of the expansion tie rod 11 is carried out by means of a hollow nut 12 which contains a key 13 and is coupled to said tie rod by means of said key.

The nut 12 has a knurled periphery (for a purpose which will become apparent hereinafter) and is engaged on the threaded portion of shaft-end 3a, there being formed in said shaft-end an axial bore 3b in which the cylindrical body 11a of the tie rod 11 is slidably fitted.

The part P to be honed is placed within a support 14 and in floating relation to this latter, said support being flexibly mounted and locked rotationally in a carriage 16 by means of lugs 15. The carriage 16 is capable of performing an axial reciprocating movement under the action of a double-acting jack 17 which is mounted in the frame 1 and the piston rod 17a of which is rigidly fixed to said carriage.

The supply of compressed fluid to the jack 17 is controlled by two end-of-travel valves 18a and 18b, said valves being actuated respectively by means of adjustable stop-screws 19a and 1% which are fitted in the carriage l6.

Screwing of the nut 12 on the threaded shaft-end 3a (in the direction corresponding to traction of the conical tie rod 11 which results in expansion of the hone 10) is carried out by braking said nut (which nonnally tends to rotate with the drive shaft on which it is screwed), this braking action being produced by a brake consisting of a hammer 21 actuated by a single-acting jack 22, said jack being supplied by means of a valve 23 which is operated in dependence on the reaction torque of the stator 5.

Dropping of the hammer 21 onto the nut 12 (and consequently the rotational locking of said nut) is caused by interrupting the supply of fluid to the jack 2.2, this interruption being carried out periodically by means of the end-of-travel valve 18a. The duration of each operating cycle of the motor 2 can be adjusted by means of a timing system which has not been illustrated in the drawings.

The honing machine has hereinabove described operates as follows:

The hone 10 in the retracted stat e-(namely the state which corresponds to the minimum diameter of said hone) is first engaged within the part P to be honed. The part is inserted in the support 14 and the motor 2 is then started up.

The hone 10 rotates freely andtherefore without producing any resisting torque within the part P which carries out an axial reciprocating movement under the action of the jack 17. At the same time, the stator 5 of the motor 2 causes the valve Ann-1 23 to open. This valve, in series with the end-of-travel valve 180, initiates the motion and stoppage of the hammer 21, the striking action of which is controlled by said end-of-travel valve.

As soon as the hammer begins to operate and thus exerts its periodic braking action on the nut 12, the tie rod 11 is pulled back by the assembly 12-13 and causes expansion of the hone 10.

This gives rise to a resisting torque which increases the drive torque and consequently upsets the position of equilibrium of the stator which then pivots in the direction opposite to the rotation of the rotor.

The above-mentioned pivotal motion of the stator 5 stops the control action of the valve 23, with the result that the hammer 21 no longer produces action on the nut 12.

The hone has continued to operate but the resisting torque has decreased and then fallen to zero, with the result that the stator 5 returns to its initial position.

As this state of operation comes to an end, so the expansion of the hone stops, the valve 23 is inoperative and the work cycle is completed by a planing operation.

An adjustment of the range of axial translational displacement of the part P (as a result of adjustment of the stops 19a and 19b) makes it possible to produce action at will on the cone obtained within the bore of said part.

The time interval which determines the thickness of stock removed by the honing process (namely the difference in radii between the bore of a honed part and the bore of an unhoned part) is regulated on the one hand by means of the timing system employed for controlling the period of action of the motor which produced the expansion of the hone and on the other hand by adjusting the tension of the spring 8.

It will be apparent that the exemplified embodiment of the machine for honing bores as hereinabove described and illustrated in the accompanying drawings does not imply any limitation and that the honing machine may be modified in any way which remains within the capacity of those skilled in the art without thereby departing either from the scope or the spirit of the invention.

lclaim:

1. An automatic honing machine for blind-end bores having only a small annular relief groove at the bottom of the bore, said machine comprising a frame, a floating electric motor having a drive shaft supported by said frame, a stator adapted to oscillate around said shaft and resilient means for urging said stator into a position of equilibrium, an expansible hone rigidly fixed to one end of the said shaft and having a conical bore therein, and means carried by the shaft for expanding said hone comprising a conical tie rod disposed in the said bore and adapted to be moved axially when actuated by oscillation of the stator.

2. The honing machine of claim 1 wherein said frame has a member disposed above said motor in a plane substantially perpendicular to the shaft of the motor and has an arm projecting from one side of the frame which carries an adjusting screw, and a spaced pair of arms projecting from the opposite side thereof, said stator has a first arm adjacent said adjusting screw and a second arm disposed between the said pair of arms, and a spring secured at one end to said screw and at the other end to said first arm of the stator.

3. The honing machine of claim 1 wherein said means for expanding the hone comprises a hollow nut carried by said shaft and about the tie rod, a key in the nut coupling the nut to the tie rod, and means for braking the rotation of said nut comprising a hammer and fluid pressure means for periodically activating the hammer.

4. The honing machine of claim 1 comprising a carriage means for moving the part back and forth with respect to the said hone.

5. The honing machine of claim 4 comprising a double-acting jack, and fluid pressure means for actuating the jack comprisin a valve actuatedby the carria e.

6. e honing machine of claim wherein a valve which controls the supply of fluid pressure to the said jack is coupled in series with two valves which control the reverse movement of the carriage.

EDWARD M.FLETCHER JR.

UNITED STATES PATENT OFFICE CERTIFICATE OF, CORRECTION Patent No. Dated February 29,

Inventor(s) Georges Garnier It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

First page, left hand column, immediately below (21) Appln. No. 8,169" insert:

Claims priority, application France, April 17, 1969, 69 11934 Signed and sealed this 25th day of July 1972.

(SEAL) Attest:

ROBERT GOT'I'SCHALK Attesting Officer Commissioner of Patents F ORM PO-1050 (10-69) USCOMM-DC 60376-P69 1* U.S. GOVERNMENT PRINTING OFFICE: I969 0-365-334 

1. An automatic honing machine for blind-end bores having only a small annular relief groovE at the bottom of the bore, said machine comprising a frame, a floating electric motor having a drive shaft supported by said frame, a stator adapted to oscillate around said shaft and resilient means for urging said stator into a position of equilibrium, an expansible hone rigidly fixed to one end of the said shaft and having a conical bore therein, and means carried by the shaft for expanding said hone comprising a conical tie rod disposed in the said bore and adapted to be moved axially when actuated by oscillation of the stator.
 2. The honing machine of claim 1 wherein said frame has a member disposed above said motor in a plane substantially perpendicular to the shaft of the motor and has an arm projecting from one side of the frame which carries an adjusting screw, and a spaced pair of arms projecting from the opposite side thereof, said stator has a first arm adjacent said adjusting screw and a second arm disposed between the said pair of arms, and a spring secured at one end to said screw and at the other end to said first arm of the stator.
 3. The honing machine of claim 1 wherein said means for expanding the hone comprises a hollow nut carried by said shaft and about the tie rod, a key in the nut coupling the nut to the tie rod, and means for braking the rotation of said nut comprising a hammer and fluid pressure means for periodically activating the hammer.
 4. The honing machine of claim 1 comprising a carriage means for moving the part back and forth with respect to the said hone.
 5. The honing machine of claim 4 comprising a double-acting jack, and fluid pressure means for actuating the jack comprising a valve actuated by the carriage.
 6. The honing machine of claim 5 wherein a valve which controls the supply of fluid pressure to the said jack is coupled in series with two valves which control the reverse movement of the carriage. 